State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, China.
Sci Rep. 2017 Jun 13;7(1):3421. doi: 10.1038/s41598-017-03644-6.
A reduction in the particle size is expected to improve the properties and increase the application potential of high-entropy alloys. Therefore, in this study, a novel sol-gel autocombustion technique was first used to synthesize high-entropy alloys. The average grain size of the prepared nanocrystalline CoCrCuNiAl high-entropy alloys showed was 14 nm with an excellent and uniform dispersion, exhibiting a distinct magnetic behavior similar to the superparamagnetic behavior. We show that the metal nitrates first form (Co,Cu,Mg,Ni,Zn)O high-entropy oxides, and then in situ reduce to CoCrCuNiAl high-entropy alloys by the reducing gases, and the chelation between citric acid and the metal ions and the in situ chemical reactions are the dominant reaction mechanisms. We demonstrate that the sol-gel autocombustion process is an efficient way to synthesize solid solution alloys eluding the restriction of a high mixing entropy.
预计粒径的减小将改善高熵合金的性能并增加其应用潜力。因此，在这项研究中，首次使用了一种新的溶胶-凝胶自燃烧技术来合成高熵合金。所制备的纳米晶 CoCrCuNiAl 高熵合金的平均晶粒尺寸为 14nm，具有优异且均匀的分散性，表现出与超顺磁行为相似的明显磁行为。我们表明，金属硝酸盐首先形成(Co,Cu,Mg,Ni,Zn)O 高熵氧化物，然后通过还原气体原位还原为 CoCrCuNiAl 高熵合金，柠檬酸与金属离子之间的螯合作用和原位化学反应是主要的反应机制。我们证明了溶胶-凝胶自燃烧过程是一种有效的合成固溶体合金的方法，可以避免高混合熵的限制。
